Improvement in telegraph-signal boxes



` t' and brake-wheels d and e.

d lvrrnn lScrn'rns THOMAS A. EDISON, OF NEWARK, NEW JERSEY, ASSIGNOR TOAMERICAN DISTRICT TELEGRAPH COMPANY, OF NEW YORK, N. Y.

IMPROVEMENT IN TELEGRAPH-SIGNAL BOXES.

Specification forming part of Letters Patent No. 146,812., dated January27, 1874 application tiled December 3, 1872.

To all whom t may concern:

Be it known that` I, TrioMAs A. EDISON, of Newark, in the county ofEssex and State of New Jersey, have invented an Improvement inTelegraphic Alarm and Signal Apparatus, of which the following is aspecification:

Before my invention, an alarm apparatus and local telegraph had beeninvented for communicating from several houses or buildings in atelegraphic circuit with the central station, for calling police,messenger, or other service, as seen in Letters Patent No. 127,844,granted to E. A. Calahan. My invention is an improvement upon the same,and a modification of Letters Patent No. 129,526; and consists iu anadjustment to the springs that close the circuit, whereby the V- shapedends are properly positioned, and the powerA of the springs regulated.Also, in arranging the magnet, armature, and adjustable stops inrelation to the clock-work sol that the parts are easy of access, andthe sound from the moving armature will be unconiiued.

In the drawing, Figure 1 is an elevation with the bed in section; andFig. 2 is a plan with the clock-work or train of gearing removed.

The base al is made circular, and adapted to receiving a glass shade toprotect the machine from dust; and the base is sustained by a bracket,b, that can be screwed to a window or door frame, or other convenientsupport.

` The plates c c are connected to the base a, and carry thespring-barrel and train of gearing, of any usual character, to rotatetheshaft There is a stoppin, 2, upon the wheel d that is arrested by thelever f, which lever f is mounted upon the insulated cross-shaft 3, andprovided with a linger-key, f', ouside the base, so that, by

depressing the said key f the lever f is Y moved, the pin 2 liberated,and the train of gearing allowed to move, and revolve the wheels d ande. The saine movement breaks the'electric circuit that ordinarily passesfrom the binder 4, through the insulated switch 5 and wire, to the leverj'; thence, through the j pin 2 and clock-work and bed, to the binder 6.

In the brake-wheels d c are notches, positioned `to give indicationsupon a suitable instrument at the central receiving-stationsuch as abell-magnet, armature, and hammer-to designate, by the strokes on thebell, the number allotted to the wheel d, or to the wheel e, and, in sodoing, indicate the station at which the instrument is placed containingsuch numbers and, also, what is wanted--such as police or messenger.

The switch k is employed to direct the cirs s cuit through either thewheel d or the wheel e, according to what is to be indicated at thereceiving-station. I remark that the contactblocks 10 and 1l of theswitch are sufficiently near each other for the circuit not to be brokenin the act of moving the switch froi'n` one contact-block to the other.s The circuit-closing springs l n are upon in-- sulated blocks, andconnected by clampingscrews passing through slots, so that the V- properlength of pause between the pulsations. s

The electro-magnet m is in an opening in the base a below theclock-work, and it is provided with an armature, p, and levert, having alimited motion between the adjustingscrews 13 14, and the `retractile`spring 15 is adjusted by the shaft 1 6, that passes through the framesc. This arrangement renders the parts very compact, gives access to themagn et from below, and brings the ,moving end of the armature-leverwhere it can be` seen, and the sound thereof against the screws 13 14will not be confined. y

The connection from thegbinder 4, through the insulated switch 5 to thelever f, ordinarily remains closed, and forms a shunt tothe main line,cutting out the electro-magnet; but, when broken at `5, the current iscompelled to go s through the electro-magnet m, producing a motion ofthe armature, and` sound. This switch 5 is, therefore, only employed byan operator PATENT OFFICE..

There are insulated to ascertain whether or not the line is in use byany other instrument, by compelling any pulsation to pass through hismagnet, and if the electro-magnet is not vibrated the line is clear, andhis own instrument een be started, and, by the electro-magnetresponding, it will become apparent that the line is in properoondition.

I claim as my inventionn 1. The oireuitsprings In, attached by slots andscrews, so as to be adjustable in their length and power, as set forth,in Combination with the wheels d e, as speoied.

2. The combination of the elect-romagna?. m beneath the clock-Work, theadjusting armature-lever, screws 13 14 outside the clock-work, and theshaft 167 for adjusting the spring, 15 above the lever and through theclock-plates c c, all arranged as and for the purposes set forth.

Signed by me this 26th dey of November,

THOMAS A. EDISON. Witnesses GEO. T. PINGKNEY, (3i-IAS. H. SMITH.

